Does anybody know why one of my plants does not want to grow? They were planted the same time. But one hasn’t done anything in a while

I've had this happen. I think its because it didn't shed its shell and allow it to get proper light. Its not a seedlings or root issue I believe. But this is a test. Why would Mr.Growit ask it, he's the pro.

Can you give us some more information? How many days since they sprouted from the medium? They spouted on the same day? What light are you using and how far away is it from the top of the plants? I've gotten dud plants like that before; sprout from the medium and then eventually keel over and die all while another seedling next to it is thriving.